That "is exactly what we see in big cities like New York and strong urban cores around the world. If everyone were driving, there would be incredible congestion issues. Yet these places are the centers of innovation and creativity and everything else that social interaction depends on," Farber said in an interview.
His research looked at census tract data in the nation's 42 largest cities. It used a supercomputer at the university to crunch numbers about how easily people could likely get together with others from points throughout their area within a couple hours after work based on the local urban design.
The research found three problems that most seriously limit social interaction: sprawl, or "decentralization"; fragmentation, or urban areas that leapfrog over open spaces; and long commute times.
"Decentralization has roughly 10 times the negative impact of fragmentation, and about 20 times that of longer commute times," Farber said.
"When people are closer to one another, there's a lot more opportunity for them to interact," he said. "Social activities promote the relationships, share knowledge and experiences that build valuable social capital that will make the cities of the 21st century more successful and globally competitive."
The research has interesting implications for local officials working as the Wasatch Choice for 2040 Consortium trying to figure how to handle expected 67 percent growth along the Wasatch Front by 2040.
That group has pushed the idea that instead of expanding urban sprawl with single-family homes, maybe a third of the population would start to cluster in new town centers built around mass-transit stations that replace old, rundown areas.
The consortium envisions that many people would live in buildings that have businesses on the first floor, offices on the second and residences above that. Town centers would be designed to allow people to live, work and play in the same area so they would commute less.
Farber said such mixed-use town centers are "definitely better than the alternative, which is sprawling suburbanization intermixed with strip malls and big-box retailers. There's no question that creating these centers will be better than what has been business as usual."
However, he said perhaps even better for socialization would be developing a stronger urban center, instead of many subcenters.
"If you were to ask me what's a more efficient use of political capital and the efficient use of infrastructure that already exists … it seems to me we've got a lot of open space in our downtown core that could be filled in before trying to artificially produce new centers out in suburban centers," he said.
"I'm looking out my window. I live downtown. I'm seeing vacant commercial spaces right here at Main and Third. I'm seeing huge parking lots in every direction. These are all spaces that could be used for much more efficient purposes, and all the people coming to these places could take advantage of all the transit investments that have already been made," he said.
Obstacles to urban social interaction
1 • Decentralization
2 • Fragmentation urban areas that leapfrog over open spaces
3 • Long commute times
Source: Urban Sprawl and Social Interaction Potential, Journal of Transport Geography